The well-known method of packaging liquid products, such as milk, fruit juices, and others, is to use parallelepipedic leak-proof containers formed by folding and pasting a sheet of a non-rigid material, such as waterproofed cardboard.
The upper part of these parallelepipedic containers is made of the ridge obtained by pasting together the edge of the larger opposite surfaces, and by two small beaks or horns folded against the two smaller surfaces when storing the container.
A container such as these can be opened by clipping one of the beaks with scissors or any similar instrument, after this beak has been pulled up.
The users are well aware that, notwithstanding their indisputable advantages, these containers present significant drawbacks: they are often difficult to open; the hand pressure on the container sides for opening, handling, and pouring may cause accidental spilling through the clipped beak, and therefore a loss of product; the product may deteriorate by oxidization or may take a bad taste when stored in a refrigerator with strong smelling food (e.g., some processed meat, cantaloupe, etc.).
These disadvantages create, in fact, three problems related to the opening, handling and closing of the container between pourings.
Previous attempts to solve these problems were never quite complete nor perfect.
Such is the case of the West German patent DE-A-2932886 which describes some kind of elastic pincers used to provide the tearing of the beak, and also the reclosing of the container; but theoretically, the reclosing is problematic.
Anyhow, even with the use of this pincer, the container must still be held directly by hand for the opening, closing and pouring operations, which is the cause of the undesired gushing due to the pressure of the fingers.
The device disclosed by West German patent DE-A-3019745 is much better in the sense that a frame with a handle is provided to lodge the container; a cross-cutting device for clipping the tip and the pulled up beak is supported by a stirrup articulated on the frame.
Although this last patent seems to solve the problem of spilling liquid when handling and opening the container, it provides no solution for insuring an airtight closure of said container.